Not Applicable
Not Applicable
1. Field of the Invention
This present invention relates to a novel side mounted light emitting diode LED and more particularly to a novel side mounted LED for thin profile side and back lighting with a pre-selected molded collimating optical element and which may also be formed as a low-profile, surface mounted side sensing photo-transistor. The invention also relates to a novel method of manufacture of the devices.
2. Description of Related Art
To miniaturize lighting and photo circuits operating parallel to the board, low profile LEDs which can produce a controlled side-emission (at a wavelength between 360-2200 nm) and low profile side sensing photo-transistors are useful. Those familiar with board parallel lighting and photo circuits will recognize that the standard procedure for assembly of such components is a through-hole mounted device which normally requires manual bending of the lead wires to achieve alignment.
One prior art method for reducing the cost of manual alignment and allowing for robotic assembly of a snap-in through-hole sideways mounted LED is taught in U.S. Pat. No. 4,897,769, issued to Lang in which an LED, fitted with a snap-in carriage may be robotically assembled.
The art of circuit mounting and light-emitting diodes is plentiful with prior art reductions to practice. One attempt to minimize LED height is taught by Orton in U.S. Pat. No. 5,331,512, wherein an LED is surface mounted on the reverse side of the board and the light is emitted through a hole in the board. The problem of parallel board surface mounting was addressed in U.S. Pat. No. 4,781,960, issued to Wittes, wherein the LED is affixed to a separate housing to accomplish board alignment and surface mounting. Many other prior art devices have surface mount features. The prior art is however void of a side light-emitting diode, or emitter/receptor photo-transistor, suited for surface mounted pick and place assembly with free-end contacts.
An LED with free-end contacts, which protrude from the substrate body of the LED eliminates the circuit failure resulting from contact and substrate separation found in LED and photo-transistor devices with substrate bonded contacts and which often de-bond due to the expansion rate differentiation between contact and substrate or mechanical shock.
While some prior art LEDs may allow for pick and place assembly and surface mounting, the unique flat top and flat bottom of the LED of the current invention, eliminates the need for up or down orientation during assembly and makes the LED self-aligning thereby reducing the defect rate.
Other novel features or improvements include a parallel optically shaped output, relative to the board, making the present invention ideal for use as in for low-profile optical circuits, miniature illumination, and as an IR emitter/collector in touch screen displays.
Accordingly, it is an object of the invention to provide a novel or improved low profile light emitting diode, or collector/emitter which may be surface mounted and which produces a controlled side-emission from 360-2200 nm.
It is yet another object of the invention to provide a novel or improved low profile light emitting diode, or collector/emitter which may be surface mounted with pick and place assembly.
It is yet another object of the invention to provide a novel or improved low profile light emitting diode, or collector/emitter which may be produced with fan angles in a pre-selected planar path from 5 degrees to 90 degrees measured parallel to the board.
It is yet another object of the invention to provide a novel or improved low profile light emitting diode, or collector/emitter with an integral optical lens.
It is yet another object of the invention to provide a novel or improved low profile light emitting diode, or collector/emitter with free-end contacts.
It is yet another object of the invention to provide a novel or improved low profile light emitting diode, or collector/emitter which is self-aligning.
It is yet another object of the invention to provide a novel or improved method of manufacture for a low profile light emitting diode, or collector/emitter with a flat top and bottom mounting surface unmarred, by gate marks, shut-offs or flashings.